Projectors are generally devices that integrate light sources, optics systems, electronics, and displays for projecting images from computers or video devices onto walls or screens, for large-image viewing. They are especially popular among business users who give presentations as part of their job responsibilities. Newer projectors can weigh as little as a few pounds, making them well suited for business travelers. As the quality of projection technology has improved, projectors are also finding their way into peoples' homes for high-definition television (HDTV) and other home entertainment applications. Some industry pundits predict that digital projectors will also become the standard projection technology used in movie theaters.
Typical projectors include spatial light modulators (SLM's) to modulate light spatially, so that images are projected onto screens for viewing. Light is transmitted, usually as one or more beams, to an SLM, which processes the light so that the desired image is projected onto a screen. Historically, SLM's have been transmissive in nature. Light is transmitted through an SLM, which modifies the light in accordance with the image to be projected onto the screen. An example of this type of SLM is a liquid crystal display (LCD). However, transmissive SLM's are disadvantageous in that the resulting projected images are dim, due to the light having to travel through the SLM's.
More recently, SLM's have been reflective in nature. Light is reflected off an SLM, which modifies the light in accordance with the image to be projected onto the screen. The archetypical example of this type of SLM is the digital micromirror device (DMD), and projectors that employ such SLM's are known as digital light processing (DLP) projectors. DLP projectors project brighter images, because the light does not have to transmit through the reflective SLM's. However, reflective SLM's are expensive devices, resulting in less-than-widespread usage of DLP projectors. For these and other reasons, therefore, there is a need for the present invention.